21838679 has 2 divisors, whose sum is σ = 21838680. Its totient is φ = 21838678.

The previous prime is 21838669. The next prime is 21838723. The reversal of 21838679 is 97683812.

It is an a-pointer prime, because the next prime (21838723) can be obtained adding 21838679 to its sum of digits (44).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21838679 - 2²⁰ = 20790103 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21838639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10919339 + 10919340.

It is an arithmetic number, because the mean of its divisors is an integer number (10919340).

Almost surely, 2^21838679 is an apocalyptic number.

21838679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21838679 is an equidigital number, since it uses as much as digits as its factorization.

21838679 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 44.

The square root of 21838679 is about 4673.1872421293. The cubic root of 21838679 is about 279.5173615772.

The spelling of 21838679 in words is "twenty-one million, eight hundred thirty-eight thousand, six hundred seventy-nine".